JBL 4401s

[oznob]

Yesterday, I stopped by The Zilchters to see what he had been up to. Oh, took the L111A's for the L110's to Daniel at Audivex to get a re-foam. Anyway, having not seen this thread I was curious about the two ways in the "ancient" looking cabinets, no ports BTW, with the very familiar looking woofers. an acoustic suspension cabinet with 123 woofers?

Without much prompting, Zilch fired them up with some Jazz, Little Feat and others and what came out was nothing short of amazing! Tight, yes tight, punchy accurate bass, smooth highs and killer mids! Piano and acoustic guitar just jumped out of them. Cymbal crashes with good sustain and shimmer. Kick drums that sound like kick drums with no slop. Almost seemless transition from the horns to the woofers. I have listened to and had my share of L100 type speakers and these clearly bested all of them. The 123 seems to beg for an acoustic suspention cabinet, properly damped, getting frequencies below 1200 HZ. Kuddo's to Zilch for putting together what I feel is one of the best two ways I have ever had the pleasure to listen to!

[johnaec]

Yeah, I stopped over later myself. Those 2-way's really work well. I'd just gotten out of 3 hours of probably 95-100dB band rehearsal, so I don't know how much I could trust my ears, but they certainly played flat, with those little neodymium HF drivers putting out crystal-clear highs. And obviously, you're not going to get earth-shaking bass out of that particular 12, but in those cabinets, they far outshine the original L100's in terms of bass extension and smoothness.

I'm really surprised JBL hasn't come out with a nice 2-way home system similar to these. The nearest comparable I can think of is 4425's. Of course, with all the used L100T's and such available at low prices on eBay, whether it's a marketable idea or not, I don't know...

John

[oznob]

Great observations John, maybe your next project?. Sorry we couldn't hook up yesterday. Mayby when I come down and get the 111's?

[Zilch]

Quasi 3-way filter w/adjustable mids and highs derived from 4425's N3124.

Check me HF, please. I haven't built from this redrawn schematic yet; presently using HF section of factory crossovers:

http://www.jblproservice.com/pdf/Net...%20Network.pdf


HF gets additional fixed L-pad attenuation before the driver, value to be determined. (It's an adjustable right now; gotta measure stuff to get it right.)

Gonna try an inexpensive active biamp approach using T-amp for HF later this week. Parts in transit....

[Zilch]

Thanks John and Oznob for coming by to listen and reporting your "findings" here.

I'm kinda stunned by these, myself.

[Must be the 10,000 monkeys in play at ZilchLab.... ]

[Zilch]

... they certainly played flat, with those little neodymium HF drivers putting out crystal-clear highs.

I've been liking this driver/horn combination since the first of this year:

http://audioheritage.org/vbulletin/s...0134#post90134

[Had to use it in something.... ]

[alexkerhead]

I am glad to hear they are sounding great, I should be able to start mine over the thanksgiving week.

[Zilch]

In designing your boxes, Alex, consider that mine are now elevated such that the horn axis is 29" off the floor. Given the 50° vertical beamwidth, I have found that to be minimum height for seated listening. It also reduces the boundary reinforcement of bass from the floor.

I'll end up with either a plinth or tall legs under these.

[Or Eames table bases, or Nelson slat bench, or.... ]

[alexkerhead]

Is the difference severe enough to HAVE to have the raised?
Because mine will HAVE to be close to the ground.

[Zilch]

It depends upon how far away from them you are listening.

Plot the 50° vertical beamwidth window from the proposed horn axis height.

Another option is tilting them back, i.e., "aiming" them upward somewhat.

I'm not sure you understand what I'm saying above, really. What I mean is consider making your boxes taller, and shallower and/or narrower to raise the horn axis height, while maintaining the 3 cuft internal volume.

Woofer moves up with the horn.

Another option: stack the horns on top of the woofer boxes, which are inverted so the woofer's at the top. That moves the horns up to listening height. Build separate matching enclosures for the horns later, like Altec Model 19....

[Zilch]

I THOUGHT I had an easy approach to biamping these: T-Amp, active XO, DONE!

Not so FAST, Zilchster. Seems everybody has a different definition of "CD compensation." Of these three (top,) only the venerable 5235 with FFBREQ cards worked for this combination of drivers, though its dip at 3 kHz is too deep.

CCBREQ doesn't have the dip, but I don't have a set of those cards at 1.2 kHz, or specs for how to make them.

Sonic Impact T-amp (silver, lower right in first pic) is barely on running these compression drivers.

They all flatten the HF well enough, it's the summing that doesn't happen. Behringer (results not shown) leaves a bigger hole than the M553 (center).

Voltage drives tell the tale, bottom. Crossings from the LF drives: 5235 = -3 dB, M553 = - 6 dB, Behringer = -12 dB???

It looks to me like the Behringer calibration is just, well, wrong. It SAYS 1K2, but it's actually more like 800 Hz. I like that it goes flat at UHF, tho, for reasons discussed elsewhere here. Also, it has adjustable delay for the woofer, which works for time alignment on these.

None of them sound particularly bad, actually. Without measuring, I probably wouldn't even know.

[Series 60 comp and CCBREQ left yet to try....]

[alexkerhead]

I have a couple small problems.
1. I do not own and cannot afford a active crossover.
2. It is unlikely I will be bi-amping them(maybe bi-receivering them).

Do you think this project is worth my trouble if it won't sound good setting on the small legs and being powered by a pioneer sx-1250?
If you don't think I should worry with it, I have some other stuff I can use the project money for.

I wouldn't want to build something that didn't sound good on what I own.

[Zilch]

Do you think this project is worth my trouble if it won't sound good setting on the small legs and being powered by a pioneer sx-1250?

50° vertical beamwidth is double axis height at 51.46" from waveguide acoustic center. [Oh NO, it's friggin' TRIG!! ]

Also see http://audioheritage.org/vbulletin/s...182#post135182

[How high are yer ears? ]

[Zilch]

1. I do not own and cannot afford a active crossover.
2. It is unlikely I will be bi-amping them(maybe bi-receivering them).

Price out the parts to build the passive crossover posted @#64, above.

I'm merely exploring biamping as a potentially cost-effective alternative; they sound spectacularly good with the passives.

The T-amp for the HF is $28 at Parts Express:

http://www.partsexpress.com/pe/showd...number=300-952

The Behringer XO I tried is $129:

http://www.partsexpress.com/pe/pshow...number=248-668

BUT, the JBL 5235 works the best so far, and Giskard is now helping us figure out how to make what may turn out to be the correct EQ cards for these:

http://audioheritage.org/vbulletin/s...ad.php?t=13202

5235s go for as little as $35 on eBay. The cards can be easily made from scratch on perfboard for just a few bucks.

Read up 5235. It's got a selectable subsonic filter built in to protect your woofers from altered consciousness, as well. I'm hoping I can make it work as an option to the passives with these:

http://www.jblproservice.com/pdf/Vin...5%20manual.pdf

I wouldn't want to build something that didn't sound good on what I own.

Send me your baffle layout, and build the boxes. You are but $50 away from a major revelation....

I have some other stuff I can use the project money for.

PS3?

[alexkerhead]

PS3?

I understand the beam width of the horns and my seating arrangement should be just right for the center axis at the proximity.

PS3? LOL, perhaps you haven't seen what I play games on?
http://ubertech-museum.com

Take a look, I don't actually play any video games, but I do collect vintage computers on top of my audio addiction.


Thanks for the 5235 recommend zilch.
I don't have enough money for birch yet, but I am getting there. Just had to buy some books for next semester, just the cisco book I needed was over a hundred bucks.